Improvement in valve-gears



ATTORNEYS.

J. G. DEAN. Valve-Gear.

Patented Z27 mw' a/r/ UNITED STATES PATENT 'OFFIGE.

. JOHN o. DEAN, or INDIANAPOLIS, INDIANA.

IMPROVEMENT IN VALVE-GEARS. V

Specification forming part of Letters Patent No. 221.537, dated November11, 1879 application filed September 19, 1879.

To all whom it may concern:

Be it known that I, JOHN C. DEAN, of Indianapolis, in the county ofMarion and State of Indiana, have inventedanewand Improved Valve-Gear,of which the'following is a specification.

Figure 1 is a longitudinal sectional elevation of the device, showingthe auxiliary valve and the main piston centered. on line z 2, Fig. 4.Fig. 2 is a sectional elevation on line or m, Fig. 1. Fig. 3 is asectional elevation, showing the auxiliary valve and main piston whennear the end of a stroke. Fig. 4 is a transverse sectional elevation online y y, Fig. 3.

Similar letters of reference indicate correspondin g parts.

The object of this invention is to provide an improved valve-gear forthe more easy and economical working of steam-pumps.

The invention consists of an arrangement in the steam-chest of adirectacting steam-pump of an auxiliary piston and valve that are sooperated as to regulate the admission and exhaust of steam to and fromthe main steamcylinder, and prevent loss of steam when the pump is inoperation.

A represents a piston, and B a piston-rod, working in a steam-cylinder,O. D is a plain slide-valve, which works over the three ports F, G, andH of the cylinder 0. I is the steamchest, the ends of which are boredcylindrically to receive the piston K, which moves the valveD. Lis anauxiliaryexhaust-valve, that works over the ports M N0 ofthe steam-chestI, above the hollow piston K. The stem P of the valve-L has an eye onits outer end for receivin g the pin Q, which projects from the upperextremity of the cam-lever R, pivoted on the stud S, projecting from thepawl W. I

T is a dog fastened to the piston-rod B, and moving with it, and havinga pin, U, that moves in the groove V of the cam-lever R. a is thesteam-ingress-portinto the steam-chest I.

Referring to Fig. 1, suppose the steam to be passing into thesteam-cylinder 0 through the port F, the piston A will then move fromleft to right in the direction indicated by the arrow, carrying with itthe dog T and pin U, causing the latter to pass along the groove V ofthe cam-lever B. As the piston A approaches the end of the stroke, thepin U will come in contact with the upper flange, b, of the cam-lever R,and will throw the cam-lever B into the tilted position shown in Fig. 3.

M O are the ports leading to the cylindrical ends of the steam-chest I.The piston K is hollow, and is provided with a small hole, 0, for theadmission of steam thereto.

a fare small holes in either end of the piston K, to permit the steamentering at c to pass into the cylindrical part of the steam-chest I, inwhich said piston K works, in order to produce an equal pressure on eachend of said piston K.

When the valve L is thrown in the position shown in Fig. 3that is, so asto throw the ports m and it into communication and to close the port 0,which results from the tilting of lever B, as before stated-the steam atthe lefthand end of the piston K can escape through ports M N, and Mbeing of a much larger area than the hole (I in the end of piston K, thesteam escaping from the left-hand end of the steam-chest I through thesaid port M destroys the equilibrium of the said piston K, and allowsthe steam at the right-hand end of the piston K to move it from right toleft, carrying with it the valve D, as clearly represented in Fig. 3,and this movement of the valve D permits the steam in the steam-chest Ito enter the port H on the right of the piston A, and at the same timepermits the escape of the exhaust-steam through the port F, thus causingthe piston A to reverse its motion and travel from right to left.

When the pistonAbegins to move from right to left the pin U will come incontact with the lower flanges, g, of the cam-lever It, and in movin gthis pin U will take the direction shown by the dotted lines shown inFig. 3, and cause the cam-lever R to swing to the position shown inFig. 1. This movement causes the valve L to be thrown into the positionshown in Fig. 1, thus closing the ports M O. The valve L continues inthis position until moved by the camlever B by means of the pin U as thepiston A reaches the opposite end of its stroke, when the motion of thevalve L is reversed in precisely the same manner as before described.

Steam is admitted to the chamber of the valve L through the passage mfor the purpose of holding the valve to its seat. The piston K could beoperated by a valve like 1), the ports M 0 being used for both admittingand exhaustingstealn, the said valve, of course, being long enough tocover both the ports when it is on acenter, as shown in Fig. 3.

Instead of the cam-lever R having a groove on it, as shown, it mighthave arih on it, over which a fork could be fitted, the fork taking theplace of the pin U. Such an arrangement would, of course, produce thesame results as the present arrangement.

I am aware that its is not new to operate the piston of anengine-cylinder by a tappet and a rocking arm, the latter connected withthe valve of an auxiliary cylinder, so as to admit and exhaust steam bythemovemcnt of the piston of the principal cylindeghnd thus actuate thepiston of the auxiliary cylinder; but

What I claim as new is---= The combination, with cylinder A, havingpiston, ports, main valve, and auxiliary valve, substantially as shownamhdescrihed, of piston-rod B, having dog with pin U, the ca lever B,having flanges g, groove V, and pin Q, and the rod P, having eye atouter end, all

constructed and arranged as and for the pur pose specified.

e JOHN G. DEAN. Witnesses:

EDWARD H. DEAN, W. R. DEAN.

